Sorry, just can't really recover from trauma of counting spaces and messing up newlines, etc. when writing Helm templates. You know, Lisp "sucks" because "you need to count parenthesis" (you actually don't), yet Helm is a widely accepted technology where you need to count spaces for (n)indent ;)
Even the helm infrastructure that I work in is completely wrapped in custom shell scripts that call all sorts of other commands to populate helm variables.
But yeah it's silly that helm templates require all sorts of {{ indent | 4 }} type incantations when the final YAML output is just sent through some kind of toJSON anyway.
When that's the case, bash if often the better choice, especially if you know it well. It has an excellent REPL, is easy to trace and is already installed everywhere.
That's a totally fine trade off for actual sane array/list functionality, robust string manipulation etc. I'd rather form shell commands in a programming language than in bash. People seem to love it.
I do not think for a second though that the average person that "knows bash well" can read and comprehend a multi hundred line bash script written by someone else as fast or even correctly has a seasoned python dev reading python written by someone else.